. >> we did evaluate the threat stream and we determined that the security at benghazi was appropriate for what we knew. >> reporter: but just the day before the attack, there were warning signs. al qaeda's leader urging libyans to retaliate against americans for the death of a libyan-born militant. and the state department was aware that that anti-muslim movie was airing on egyptian tv. yet, there were no warnings about it to other u.s. missions. why there weren't warnings about the movie is a big question tonight. given that whenever there's been any denigration of the prophet of muhammad, demonstrations and violence have almost always followed, diane. >> thank you so much, martha. and our thanks to jeffrey, too. more on that now, because, tonight, finally, we have some facts about the mysterious man who created that anti-muslim movie, the inflammatory movie that sparked extremist reaction around the world. that man is still in hiding, still in the shadows. so, what was his motive? we asked abc's chief investigative correspondent brian ross to find out. >> reporter: police and report